The invention relates to a suction refill valve for a master brake cylinder. Suction refill valves are used in the master brake cylinder for filling brake systems, for instance in motor vehicles. In the aspiration position of the brake pedal, in the pressureless state, an exchange of fluid between the supply container and the brake system takes place and thus assures a uniform brake system fill level. In brake systems having brake slip control, the volumes of fluid in the static brake systems are varied, producing considerable differences in pressure when these refill valves are opened. The suction refill valves are also part of the brake slip control. For this application, not only must the suction refill valves be pressure tight, but they must also be capable of being opened and closed at high pressure without being damaged. Since they are opened by spring force, the opening force must also be as low as possible.